So 



HARD WICKKS SCIENCE- G OS SIP. 



out of the way. For picking specimens out of the 

 cell there is nothing so handy as an ordinary section- 

 lifter with a rather small blade. Searching in this 

 way, the more peculiar specimens may be separated 

 and set aside. Those that are intended for examina- 

 tion alive must be placed in a relatively large bulk of 

 water, as they soon die if left for any length of time 

 in a confined space. 



While this preliminary examination is going on, 

 the process of preserving the much larger portion not 

 reserved for immediate examination may be proceeded 

 with. For this all that is required is a glass funnel 

 in which has been placed a piece of muslin, arranged 

 like a filter-paper, and a couple of pickle-bottles, one 

 of which contains a few ounces of rectified spirit. 



As soon as a trayful has been looked over, its 

 contents should be turned into this funnel, and the 

 water allowed to drain off into the empty bottle. As 

 soon as the whole has been collected in this way, a 

 little fresh water is allowed to run through, to wash 

 out the remaining salts, and, the bottle having been 

 emptied, the spirit in the other is poured in and 

 allowed to run through. The funnel is then shifted 

 to the now empty bottle and the spirit poured through 



less dissolve and render brittle the delicate calcareous 

 shells of Pteropods and other small mollusks. It 

 may, however, be advantageously employed in cases 

 where for any reason a liberal supply of alcohol may 

 not be obtainable, as a much smaller bulk of glycerine 

 will suffice for the purpose. 



When a large catch has been made it is well to 

 have two or three funnels at work, as it is very 

 important to get the specimens spirited as soon as 

 possible. To show the amount occasionally obtained, 

 I may mention that on one occasion the mass taken 

 in a single haul of the net, left out for the night, was 

 sufficient to more than half-fill an ordinary pickle-jar. 



Fig. 54- — Aerating Apparatus applied to Live Cell. 



again. By repeating this process two or three times 

 the specimens are very rapidly and completely 

 deprived of the greater part of their water. 



The muslin is then gathered into a bag and sus- 

 pended in a jar of " 580 s.g. spirit for twenty-four 

 hours, after which the mass may be removed from 

 the muslin and stocked in small, wide-mouthed 

 bottles of spirit. If for this purpose absolute alcohol 

 be employed, the specimens may be allowed to half- 

 fill the bottle. With ordinary rectified spirit a more 

 liberal proportion of spirit must be allowed. When 

 engaged on daily work a considerable economy may 

 be effected, by keeping the used spirit and employing 

 it to extract the thick of the water from the next 

 day's specimens. Prepared in this way, the specimens 

 will keep for an indefinite time. 



An alternative plan is to treat the mass in the 

 muslin with glycerine in the same manner. This 

 has the advantage of preserving the organisms in a 

 beautifully clarified condition ; but the treacly con- 

 sistence of the medium does not lend itself so well to 

 the subsequent process of sorting the specimens, and, 

 moreover, the glycerine has a tendency to more or 



Fig. 55. — Aerating Apparatus. 



A couple of hours is however quite long enough to 

 leave the net, as a rule, as beyond that time the 

 things first caught are apt to get damaged. 



It is always worth while to examine some one 

 species of each catch in the living state. For this 

 purpose three or four, if obtainable, should be set 

 aside in a good sized bell-glass of sea-water, as they 

 die so rapidly in the contracted limits of a live cell 

 that several subjects may be required for a complete 

 examination. Apart from the wonderful view of their 

 internal economy which their great transparency 

 enables one to obtain, the movements of the animal 

 allow of one's forming a much better idea of the 

 relations and functions of its parts than can ever be 

 got when dead, as then it is kept by gravitation 

 obstinately in one position, in any other than which 

 it will be found extremely difficult to retain it. 

 (To be continued.) 



We regret to record the death of Mr. W. W. 

 Leighton, who since the year 1867 has filled the 

 office of Clerk of the Geological Society of London. 



